LCM( 12, 16, 20 ) = 240
Step 1: Write down factorisation of each number:
12 = 2 · 2 · 3
16 = 2 · 2 · 2 · 2
20 = 2 · 2 · 5
Step 2 : Match primes vertically:
12 | = | 2 | · | 2 | · | 3 | ||||||
16 | = | 2 | · | 2 | · | 2 | · | 2 | ||||
20 | = | 2 | · | 2 | · | 5 |
Step 3 : Bring down numbers in each column and multiply to get LCM:
12 | = | 2 | · | 2 | · | 3 | ||||||||
16 | = | 2 | · | 2 | · | 2 | · | 2 | ||||||
20 | = | 2 | · | 2 | · | 5 | ||||||||
LCM | = | 2 | · | 2 | · | 2 | · | 2 | · | 3 | · | 5 | = | 240 |
This solution can be visualized using a Venn diagram.
The LCM is equal to the product of all the numbers on the diagram.